Help/UGens/FFT/Convolution2L.html

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  31 <p class="p1"><span class="s1"><b>Convolution2L<span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span></b></span><b>real-time convolver with linear interpolation</b></p>
  32 <p class="p2"><br></p>
  33 <p class="p1"><b>Convolution2L.ar(in, kernel, trigger, framesize, crossfade, mul, add)</b></p>
  34 <p class="p2"><br></p>
  35 <p class="p1">Strict convolution with fixed kernel which can be updated using a trigger signal. There is a linear crossfade between the buffers upon change.</p>
  36 <p class="p3"><br></p>
  37 <p class="p1">See Steven W Smith, The Scientist and Engineer's Guide to Digital Signal Processing:<span class="Apple-converted-space"> </span></p>
  38 <p class="p1">chapter 18: <span class="s2">http:// www.dspguide.com/ch18.htm</span><span class="Apple-converted-space"> </span></p>
  39 <p class="p3"><br></p>
  40 <p class="p1"><b>in</b> - processing target</p>
  41 <p class="p1"><b>kernel</b>- buffer index for the fixed kernel, may be modulated in combination with the trigger</p>
  42 <p class="p1"><b>trigger</b> - update the kernel on a change from &lt;=0 to &gt;0</p>
  43 <p class="p1"><b>framesize </b>- size of FFT frame, must be a power of two. Convolution uses twice this number internally, maximum value you can give this argument is 2^16=65536. Note that it gets progressively more expensive to run for higher powers! 512, 1024, 2048, 4096 standard.</p>
  44 <p class="p1"><b>crossfade</b> - The number of periods over which a crossfade is made. The default is 1. This must be an integer.</p>
  45 <p class="p3"><br></p>
  46 <p class="p4"><span class="s3">See also <a href="Convolution2.html"><span class="s4">Convolution2</span></a> and <a href="StereoConvolution2L.html"><span class="s2">StereoConvolution2L</span></a>.</span></p>
  47 <p class="p2"><br></p>
  48 <p class="p5">s = <span class="s5">Server</span>.local.boot;</p>
  49 <p class="p2"><br></p>
  50 <p class="p6"><span class="s3">(</span>// allocate three buffers</p>
  51 <p class="p5">b = <span class="s5">Buffer</span>.alloc(s, 2048);</p>
  52 <p class="p5">c = <span class="s5">Buffer</span>.alloc(s, 2048);</p>
  53 <p class="p5">d = <span class="s5">Buffer</span>.alloc(s, 2048);</p>
  54 <p class="p2"><br></p>
  55 <p class="p5">b.zero;</p>
  56 <p class="p5">c.zero;</p>
  57 <p class="p5">d.zero;</p>
  58 <p class="p5">)</p>
  59 <p class="p2"><br></p>
  60 <p class="p5">(</p>
  61 <p class="p5">50.do({ <span class="s5">|it|</span> c.set(20*it+10, 1.0.rand); });</p>
  62 <p class="p5">3.do({ <span class="s5">|it|</span> b.set(400*it+100, 1); });</p>
  63 <p class="p5">20.do({ <span class="s5">|it|</span> d.set(40*it+20, 1); });</p>
  64 <p class="p5">)</p>
  65 <p class="p2"><br></p>
  66 <p class="p2"><br></p>
  67 <p class="p5">(</p>
  68 <p class="p5"><span class="s5">SynthDef</span>(<span class="s6">\conv_test</span>, { <span class="s5">arg</span> kernel, t_trig=0;</p>
  69 <p class="p5"><span class="Apple-tab-span">     </span><span class="s5">var</span> input;</p>
  70 <p class="p2"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span></p>
  71 <p class="p5"><span class="Apple-tab-span">     </span>input=<span class="s5">Impulse</span>.ar(1);</p>
  72 <p class="p2"><br></p>
  73 <p class="p6"><span class="s3"><span class="Apple-tab-span">    </span></span>// must have power of two framesize</p>
  74 <p class="p5"><span class="Apple-tab-span">     </span><span class="s5">Out</span>.ar(0, <span class="s5">Convolution2L</span>.ar(input, kernel, t_trig, 2048, 1, 0.5));</p>
  75 <p class="p5">}).add</p>
  76 <p class="p2"><br></p>
  77 <p class="p5">)</p>
  78 <p class="p2"><br></p>
  79 <p class="p2"><br></p>
  80 <p class="p5">x = <span class="s5">Synth</span>(<span class="s6">\conv_test</span>, [<span class="s7">\kernel</span>, b]);</p>
  81 <p class="p2"><br></p>
  82 <p class="p6">// changing the buffer number:</p>
  83 <p class="p5">x.set(<span class="s7">\kernel</span>, c);</p>
  84 <p class="p6"><span class="s3">x.set(</span><span class="s7">\t_trig</span><span class="s3">, 1); </span>// after this trigger, the change will take effect.</p>
  85 <p class="p5">x.set(<span class="s7">\kernel</span>, d);</p>
  86 <p class="p6"><span class="s3">x.set(</span><span class="s7">\t_trig</span><span class="s3">, 1); </span>// after this trigger, the change will take effect.</p>
  87 <p class="p2"><br></p>
  88 <p class="p5">d.zero;</p>
  89 <p class="p6"><span class="s3">40.do({ </span><span class="s5">|it|</span><span class="s3"> d.set(20*it+10, 1); });</span>// changing the buffers' contents</p>
  90 <p class="p6"><span class="s3">x.set(</span><span class="s7">\t_trig</span><span class="s3">, 1); </span>// after this trigger, the change will take effect.</p>
  91 <p class="p2"><br></p>
  92 <p class="p5">x.set(<span class="s7">\kernel</span>, b);</p>
  93 <p class="p6"><span class="s3">x.set(</span><span class="s7">\t_trig</span><span class="s3">, 1); </span>// after this trigger, the change will take effect.</p>
  94 <p class="p2"><br></p>
  95 <p class="p5">x.free;</p>
  96 <p class="p2"><br></p>
  97 <p class="p6">// longer crossfade</p>
  98 <p class="p5">(</p>
  99 <p class="p5"><span class="s8">SynthDef</span>( <span class="s6">\conv_test2</span>, { <span class="s8">arg</span> kernel, t_trig=0;</p>
 100 <p class="p5"><span class="Apple-tab-span">     </span><span class="s8">var</span> input;</p>
 101 <p class="p2"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span></p>
 102 <p class="p5"><span class="Apple-tab-span">     </span>input=<span class="s8">Impulse</span>.ar(1);</p>
 103 <p class="p2"><br></p>
 104 <p class="p7"><span class="s3"><span class="Apple-tab-span">    </span></span>// must have power of two framesize</p>
 105 <p class="p5"><span class="Apple-tab-span">     </span><span class="s8">Out</span>.ar(0, <span class="s8">Convolution2L</span>.ar(input, kernel, t_trig, 2048, 5, 0.5));</p>
 106 <p class="p5">}).add</p>
 107 <p class="p2"><br></p>
 108 <p class="p5">)</p>
 109 <p class="p2"><br></p>
 110 <p class="p2"><br></p>
 111 <p class="p8"><span class="s3">x = </span><span class="s8">Synth</span><span class="s3">(</span>\conv_test2<span class="s3">, [</span>\kernel<span class="s3">, b]);</span></p>
 112 <p class="p2"><br></p>
 113 <p class="p6">// changing the buffer number:</p>
 114 <p class="p5">x.set(<span class="s7">\kernel</span>, c);</p>
 115 <p class="p6"><span class="s3">x.set(</span><span class="s7">\t_trig</span><span class="s3">, 1); </span>// after this trigger, the change will take effect.</p>
 116 <p class="p5">x.set(<span class="s7">\kernel</span>, d);</p>
 117 <p class="p6"><span class="s3">x.set(</span><span class="s7">\t_trig</span><span class="s3">, 1); </span>// after this trigger, the change will take effect.</p>
 118 <p class="p2"><br></p>
 119 <p class="p5">d.zero;</p>
 120 <p class="p6"><span class="s3">40.do({ </span><span class="s5">|it|</span><span class="s3"> d.set(20*it+10, 1); });</span>// changing the buffers' contents</p>
 121 <p class="p6"><span class="s3">x.set(</span><span class="s7">\t_trig</span><span class="s3">, 1); </span>// after this trigger, the change will take effect.</p>
 122 <p class="p2"><br></p>
 123 <p class="p5">x.set(<span class="s7">\kernel</span>, b);</p>
 124 <p class="p6"><span class="s3">x.set(</span><span class="s7">\t_trig</span><span class="s3">, 1); </span>// after this trigger, the change will take effect.</p>
 125 <p class="p2"><br></p>
 126 <p class="p5">x.free;</p>
 127 <p class="p2"><br></p>
 128 <p class="p6">// // next example</p>
 129 <p class="p2"><br></p>
 130 <p class="p9"><span class="s3">b = </span><span class="s5">Buffer</span><span class="s3">.read(s, </span>"sounds/a11wlk01.wav"<span class="s3">);</span></p>
 131 <p class="p2"><br></p>
 132 <p class="p5">(</p>
 133 <p class="p5"><span class="Apple-tab-span">     </span>{ <span class="s5">var</span> input, kernel;</p>
 134 <p class="p2"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span></p>
 135 <p class="p5"><span class="Apple-tab-span">     </span>input= <span class="s5">SoundIn</span>.ar(0);</p>
 136 <p class="p2"><br></p>
 137 <p class="p6"><span class="s3"><span class="Apple-tab-span">    </span></span>// must have power of two framesize</p>
 138 <p class="p5"><span class="Apple-tab-span">     </span><span class="s5">Convolution2L</span>.ar(input, b, 0, 512, 1, 0.5);</p>
 139 <p class="p5"><span class="Apple-tab-span">     </span>}.play;</p>
 140 <p class="p2"><br></p>
 141 <p class="p5">)</p>
 142 <p class="p2"><br></p>
 143 <p class="p2"><br></p>
 144 <p class="p6">// another example</p>
 145 <p class="p2"><br></p>
 146 <p class="p5">(</p>
 147 <p class="p6">// must have power of two framesize- FFT size will be sorted by Convolution2 to be double this</p>
 148 <p class="p6">// maximum is currently a=8192 for FFT of size 16384</p>
 149 <p class="p5">a=2048;</p>
 150 <p class="p6">// kernel buffer</p>
 151 <p class="p5">g = <span class="s5">Buffer</span>.alloc(s, a, 1);</p>
 152 <p class="p5">)</p>
 153 <p class="p2"><br></p>
 154 <p class="p5">(</p>
 155 <p class="p5">g.set(0, 1.0);</p>
 156 <p class="p5">100.do({<span class="s5">arg</span> i; g.set(a.rand, (i+1).reciprocal)});</p>
 157 <p class="p5">)</p>
 158 <p class="p2"><br></p>
 159 <p class="p5">(</p>
 160 <p class="p6">// random impulse response</p>
 161 <p class="p2"><br></p>
 162 <p class="p5"><span class="Apple-tab-span">     </span>{</p>
 163 <p class="p5"><span class="Apple-tab-span">     </span><span class="s5">var</span> input, inputAmp, threshhold, gate;</p>
 164 <p class="p2"><br></p>
 165 <p class="p5"><span class="Apple-tab-span">     </span>input = <span class="s5">SoundIn</span>.ar(0);<span class="Apple-converted-space"> </span></p>
 166 <p class="p5"><span class="Apple-tab-span">     </span>inputAmp = <span class="s5">Amplitude</span>.kr(input);</p>
 167 <p class="p6"><span class="s3"><span class="Apple-tab-span">    </span>threshhold = 0.02;<span class="Apple-tab-span">  </span></span>// noise gating threshold</p>
 168 <p class="p5"><span class="Apple-tab-span">     </span>gate = <span class="s5">Lag</span>.kr(inputAmp &gt; threshhold, 0.01);<span class="Apple-tab-span">      </span></p>
 169 <p class="p2"><span class="Apple-tab-span">     </span></p>
 170 <p class="p5"><span class="Apple-tab-span">     </span><span class="s5">Convolution2L</span>.ar(input*gate, g, 0, a, 1, 0.5);</p>
 171 <p class="p5"><span class="Apple-tab-span">     </span>}.play;</p>
 172 <p class="p2"><br></p>
 173 <p class="p5">)</p>
 174 <p class="p2"><br></p>
 175 <p class="p2"><br></p>
 176 <p class="p2"><br></p>
 177 <p class="p2"><br></p>
 178 <p class="p2"><br></p>
 179 <p class="p2"><br></p>
 180 <p class="p6">// one last example</p>
 181 <p class="p5">(</p>
 182 <p class="p5">b = <span class="s5">Buffer</span>.alloc(s, 512, 1);</p>
 183 <p class="p5">b.sine1(1.0/[1, 2, 3, 4, 5, 6], <span class="s5">true</span>, <span class="s5">true</span>, <span class="s5">true</span>);</p>
 184 <p class="p5">)</p>
 185 <p class="p2"><br></p>
 186 <p class="p5">(</p>
 187 <p class="p5"><span class="Apple-tab-span">     </span>{ <span class="s5">var</span> input, kernel;</p>
 188 <p class="p2"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span></p>
 189 <p class="p5"><span class="Apple-tab-span">     </span>input=<span class="s5">SoundIn</span>.ar(0);</p>
 190 <p class="p2"><br></p>
 191 <p class="p6"><span class="s3"><span class="Apple-tab-span">    </span></span>// must have power of two framesize</p>
 192 <p class="p5"><span class="Apple-tab-span">     </span><span class="s5">Convolution2L</span>.ar(input, b, 0, 512, 1, 0.5);</p>
 193 <p class="p5"><span class="Apple-tab-span">     </span>}.play;</p>
 194 <p class="p2"><br></p>
 195 <p class="p5">)</p>
 196 <p class="p2"><br></p>
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